Code check plus using has("selector")

[SamC]

I'm writing a tutorial about URL segments and I have it working like this (ignore overly verbose comments).

Cats (cat-index template)
 - cat 1 (cat-entry template)
 - cat 2
 - cat 3

Type (cat-attribute template, each child is a page ref field on cat-entry template)
 - Burmese (cat-attribute template)
 - Tabby
 - Persian
 - etc.

Invalid is 2nd URL segment and anything else in URL segment 1 that isn't the page name under /type/.

Valid
/cats/tabby/
/cats/persian/
etc...

Invalid
/cats/first/
/cats/first/second/

<?php
  // only 1 URL segment should be allowed
  if ($input->urlSegment2) {
    throw new Wire404Exception();
  }

  // create a string that will be our selector
  $selector = "template=cat-entry";

  // get URL segment 1
  $segment1 = $input->urlSegment1;

  // if there is a URL segment 1
  if ($segment1) {
    // get array of cat type page names
    $catTypes = $pages->get("/type/")->children->each("name"); // name may be assumed here, not sure
    
    // if URL segment 1 is in cat types array
    if (in_array($segment1, $catTypes)) {
      
      // add this to the selector
      $selector .= ",catType=$segment1";
    }
    else {
      // invlid URL segment 1
      throw new Wire404Exception();
    }
  }

  // find the pages based on our selector
  $catPages = $pages->find($selector);
  foreach ($catPages as $catPage):
?> 

Now this works, 404 for anything invalid.

But I was looking at https://processwire.com/api/ref/wire-array/has/ and it seems to be similar.

Is the code above a suitable way to achieve this? (bearing in mind this is a tutorial so trying to stick with best practices)

And how would I use has() in the above example? Not 100% how to use that method i.e. is ->has() used inside a loop?

(unfortunately can't link to the actual tut as it's unpublished)

[Robin S]

I would do the validation a little differently, to avoid loading any more pages than you need to:

// if there is a URL segment 1
if($segment1) {
    // get catType page
    $catType = $pages->findOne("parent=/type/, name=$segment1");
    // if catType page exists
    if($catType->id) {
        // add this to the selector
        $selector .= ", catType=$catType";
    } else {
        // invalid URL segment 1
        throw new Wire404Exception();
    }
}

Not sure in what way you were considering using has(), but that method is for checking against a PageArray/WireArray that is already loaded to memory - better to load just the page (category) you want than to load many just to filter it down again.

[SamC]

6 minutes ago, Robin S said:

// get catType page
$catType = $pages->findOne("parent=/type/, name=$segment1");

Absolutely this, I like it!

6 minutes ago, Robin S said:

Not sure in what way you were considering using has(), but that method is for checking against a PageArray/WireArray that is already loaded to memory - better to load just the page (category) you want than to load many just to filter it down again.

I couldn't work out the use for it,  I see now. Thanks